Comparison GOODRAM PX600 SSDPR-PX600-500-80 500 GB vs GOODRAM PX500 GEN.2 SSDPR-PX500-512-80-G2 512 GB

Nominal drive capacity. This parameter directly determines not only the amount of data that can fit on the device, but also its cost; many SSD models even come in several versions that differ in capacity. Therefore, when choosing, it is worth considering the real needs and features of the application — otherwise you can overpay a significant amount for volumes that are not needed in fact.

In terms of actual values, a capacity of 120 GB or less is considered small these days. This can also be equated with a 240 GB SSD. Average values are already considered 500 GB, increased — 1 TB(in the range of which SSDs fall 400 and 800 GB). And the most capacious modern SSDs can accommodate 2 TB, 4 TB and even more.

Connection interface supported by an M.2 drive (see Form Factor).

All such drives use a standard hardware connector, however, different electrical (logical) interfaces can be implemented through this connector — either SATA (usually SATA 3), or PCI-E (most often in PCI-E 3.0 2x, PCI-E 3.0 4x, PCI-E 4.0 4x, PCI-E 5.0 4x). The M.2 connector on the motherboard must support the appropriate interface — otherwise the normal operation of the SSD will not be possible. Let's consider each option in more detail.

SATA 3 connectivity provides data transfer rates up to 5.9 Gbps (approx. 600 Mbps); it is considered a very simple option and is used mainly in low-cost M.2 modules. This is due to the fact that this interface was originally created for hard drives, and for faster SSD drives, its capabilities may no longer be enough.

In turn, the PCI-E interface provides higher connection speeds and allows the implementation of special technologies like NVMe (see below). The designation of such an interface indicates its version and the number of lines – for example, PCI-E 3.0 2x means version 3 with two data lines. By this designation you can determine the maximum connection speed: PCI-E version 3.0 gives just under 1 GBps per line, version 4.0 – twice as much (up to 2 GBps), 5.0 – twice as much a...s the “four” (almost 4 GBps). Thus, for example, for PCI-E 5.0 4x the maximum data transfer speed will be about 15 GBps (4 lanes of almost 4 GBps). However, we note that newer and faster drives can be connected to earlier and slower M.2 connectors – except that the data transfer speed will be limited by the capabilities of the connector.

The type of the main memory of the drive determines the features of the distribution of information over hardware cells and the physical features of the cells themselves.

— MLC. Multi Level Cell memory based on multi-level cells, each of which contains several signal levels. MLC memory cells store 2 bits of information. Has optimum indicators of reliability, power consumption and productivity. Until recently, the technology was popular in entry-level and mid-range SSD modules, now it is gradually being replaced by more advanced options in the manner of TLC or 3D MLC.

— TLC. The evolution of MLC technology. One Flash Memory Triple Level Cell can store 3 bits of information. Such a recording density somewhat increases the likelihood of errors compared to MLC, in addition, TLC memory is considered less durable. A positive feature of the nature of this technology is its affordable cost, and various design tricks can be used to improve reliability in SSDs with TLC memory.

— 3D NAND. In a 3D NAND structure, several layers of memory cells are arranged vertically, and interconnections are organized between them. This provides greater storage capacity without increasing the physical size of the drive and improves memory performance due to shorter connections for each memory cell. In SSD drives, 3D NAND memory can use MLC, TLC or QLC chips - more details...about them are described in the corresponding help paragraphs.

— 3D MLC NAND. MLC-memory has a multilayer structure — its cells are placed on the board not in one level, but in several "floors". As a result, manufacturers have achieved an increase in storage capacity without a noticeable increase in size. Also, 3D MLC NAND memory is characterized by higher reliability than the original MLC (see the relevant paragraph), at a lower manufacturing cost.

— 3D TLC NAND. "Three-dimensional" modification of the TLC technology (see the relevant paragraph) with the placement of memory cells on the board in several layers. This arrangement allows you to achieve higher capacity with smaller sizes of the drives themselves. In production, such memory is simpler and cheaper than a single-layer one.

— 3D QLC NAND. Quad Level Cell flash type with 4 bits of data in each cell. The technology is designed to make SSDs with large volumes widely available and finally retire traditional HDDs. In the 3D QLC NAND configuration, the memory is built according to a “multi-level” scheme with the placement of cells on the board in several layers. "Three-dimensional" structure reduces the cost of production of memory modules and allows you to increase the volume of drives without compromising their weight and size component.

— 3D XPoint. A fundamentally new type of memory, radically different from traditional NAND. In such drives, memory cells and selectors are located at the intersections of perpendicular rows of conductive tracks. The mechanism for recording information in cells is based on changing the resistance of the material without the use of transistors. 3D XPoint memory is simple and inexpensive to produce, and offers much better speed and durability. The prefix "3D" in the name of the technology says that the cells on the crystal are placed in several layers. The first generation of 3D XPoint received a two-layer structure and was made using a 20-nanometer process technology.

The highest speed in write mode characterizes the speed with which the module can receive information from a connected computer (or other external device). This speed is limited both by the connection interface (see "Connector"), and by the characteristics of the device of the SSD itself.

The highest data exchange rate with a computer (or other external device) that the drive can provide in read mode; in other words — the highest speed of information output from the drive to an external device. This speed is limited both by the connection interface (see "Connector"), and by the characteristics of the device of the SSD itself. Its values can vary from 100 – 500 MB / s in the slowest models to 3 Gb / s and higher in the most advanced ones.

The abbreviation TBW stands for drive time between failures, expressed in terabytes. In other words, this is the total amount of information that is guaranteed to be written (rewritten) to this module. This metric measures the overall reliability and lifespan of a drive—the higher the TBW, the longer the device will last, all other things being equal.

Note that knowing the TBW and the warranty period, you can calculate the number of rewrites per day (DWPD, see the relevant paragraph), if the manufacturer did not specify these data. To do this, use the formula: DWPD = TBW / (V * T * 365), where V is the drive capacity in terabytes, T is the warranty period (years). As for specific numbers, there are a lot of drives on the market with a relatively low TBW — up to 100 TB ; even these values are often sufficient for everyday use for a considerable amount of time. However, models with TBW at the level of 100 – 500 TB are more common. Values of 500 – 1000 TB can be classified as "above average", and in the most reliable solutions this figure is even higher.

The number of full overwrites per day allowed by the design of the drive, in other words, how many times a day the entire drive can be guaranteed to be overwritten without fear of failures.

This parameter describes the overall reliability and durability of the drive. It is similar in meaning to TBW (see the relevant paragraph), one value can even be converted to another, knowing the warranty period: TBW = DWPD*V*T*365, where V is the drive capacity in terabytes, and T is the warranty period in years . However, DWPD is somewhat more specific: it describes not only the total time between failures, but also the limit on the number of rewrites per day; if this limit is exceeded, the drive may fail earlier than specified in the warranty. However, even small DWPD values — 0.5 – 1 time per day, or even less than 0.5 times a day — often turn out to be sufficient not only for simple everyday use, but even for professional tasks. Higher rates — 1 – 2 times a day or more — are rare; at the same time, it can be both high-end and low-cost SSD modules.